Not all meditation is created equal, according to a new study.

And if you’re looking to meditate to improve something specific, you should pick a practice that focuses on the thing you’d like to improve.

Many studies have been done to show the benefits of meditation: it can make you calmer and happier and a better person. But “meditation” is actually a group of different techniques. Different methods produce different results. And a lot of the studies are somewhat faulty. Lumping together different skills and using relatively few participants.

Over a span of nine months, 300 people practiced three specific types of meditation techniques, and recorded their results in a study published today in Science Advances. They found that all three techniques — which focused on attention, empathy, and perspective-taking — caused changes in both brain structure and actual behavior. But practicing one skill doesn’t make you better at something else, so actually focusing on your breath probably won’t make you more compassionate.

The first three-month module, called “presence,” focused on attention. The second and third modules focused more on social dynamics. In the “affect” module, participants worked in pairs.  The “perspective” module was about trying to develop compassion and deal with difficult emotions. People practiced taking other people’s perspectives.

The scientists used a brain scan. That shows bloodflow to track changes before and after the meditation modules.

Crucially, though, the skills didn’t generalize. People who did the “presence” module did better at computer-based attention tests. But they didn’t do any better in measures of compassion or perspective until they took the other two modules.